Like buddha above I sample the mass market one's at department stores, most are awful but there's the odd gem. The only frag samples I've ordered were Floris No.89 & Penhaligon's Hammam Bouquet simply because I couldn't try them locally. I find Floris' 1.2ml sample for £2.50 to be the sweet spot, some companies want £5 for 3ml which is defeating the purpose of a sample IMO.
Soap samples on the other hand I used to buy quite often but came to realise that performance is very rarely indicative of the full product, their only real use is for sampling the scents.